Compressor-unloading means



p 9, E929. H. B. HALvoRsEN COMPRESSOR UNLOADING MEANS RJQSJIH Filed Feb.25, 1924 2 Sheets-Sheet l Eig.

pf 9, 1929. H.v B. HALvoRsl-:N LMSJ'H COMPRESSOR UNLOADING MEANS FiledFeb. 25, 1924 2 sheets-sheet 2 Patented Apr. 9, 11929..

narran stares y avea-,ui rarest ermee.

HALBERT B. HALVORSEN, QF MICHIGAN CITY, INDIANA, A/SSIG-NOR TO SULLIVANMACHINERY COMPANY, A CORPORATION F MASSACHUSETTS.

COMPRESSOR-UNLOADING MEANS.

Application led February 25, 1924.- Serial No. 694,926.

4 compression ot' any air which might leak past the intake unloadervalve when the compressor 1s turning over unloaded from a partial vacuumto receiver pressure. Other ob- ,jects and Vadvantages of my inventionwill be apparent in the course of the following specitication andappended claims. Y

In the accompanying drawings I have sho wn for purposes of illustrationseveral embodiments which my invention may assume in practice.

ln these drawings,-

Fig. 1 is a sectional view through one illustrative embodiment of myimproved unloading mechanism.

Fig. 2 is a similar section on the line 2 2 of Fig. 1.

Fig. 3 is an end view ofthis mechanism.

'F ig. 4 is a sectional view through a diftferent illustrative form on aplane corresponding to vthe line 4 4 of Fig. 6, parts being shown inelevation.

Fig. 5 is a section on the line 5 5 of Fig. 6.

Fig. 6 is an end view with a portion eut away to show details of theconstruction of this second illustrative `form of my invention.

Fig. 7 is a view corresponding to Fig. 4 through a third form.

As the details of construction of compressors with which mechanism ofthis type may be used are so Well known, it seems unnecessary toillustrate one of these mechanisms in 4position upon a compressor. Thegeneral disposition of these devices may, however, be observed ifnecessary in the patent to H. C. Johansen, 1,404,176,- patented J an.V17, 1922.

Compressors of the type With which thisIl mechanism is used vcomprise Wand high pressure cylinders connected by an intercooler, and the lowpressure cylinder intake is controlled by an intake closure valve. As aresult, when the compressor is unloaded, if the valve does not seatperfectly tight, there is some small leakage of air int-o the lowpressure cylinder but this is not of sutieient quantity to maintain theinter-cooler pressure as high as atmospheric pressure, for the highpressure cylinder keeps this pumped down to quite a substantial vacuumdespite the leakage. As a result, what little air does leak in must becompressed in the high pressure cylinder :trom a partial vacuum up toreceiver pressure; and there is thereby produced a very high temperature on account ofthe number of compressions, with resultant burning ofthe lubricant, dama-ge to valves and other injurious consequences. Forthe purpose of avoiding the compression 'of any air lwhich may leak in,and to vent it to the atmosphere whenever thepressure exceedsatmospheric, I have devised the invention, three illustrative forms ofWhich are shown herein.

As a preliminary it may be stated that these three forms diii'er fromeach other primarily in that use has been made of three different typesof valve mechanism, namely, the end seating or poppet type, the slidetype, and the piston type, in the three forms. Taking up the first formwhich is shown in Figs. l, 2 and 3, it will be observed that itcomprises a casing 1 from whose opposite sides pipes 2 and 3 lead to thecounterbores or clearances at the opposite ends of a high pressurecylinder of a compressor. The pipes 2 and 3 open into chambers 4 and 5respectively which are arranged at opposite sides of a chamber 6 whichopens into a larger chamber 7. Chamber 7 is in turn connected by aseries of ports 8 controlled by a thin annular valve 9 with a recess lformed in a cap member 11, there being an opening 12 leading to theatmosphere through the cap member 11. A spring 13 transversely Hexed andheld in position by a machine screw 14 serves'to maintain the valve "9normally seated but permits it to open when the pressure Within thechamber 7 is substantially above atmospheric pressure. Between thechambers 4 and 5 and the chamber 6, therearc arranged a pair of valveseats 15 and 16 respectively, these being coaxial with each other. Valvemeans including a pair of coaXially arranged valves 17 and 18 connectedby a stem portion 19 and mounted upon the upper end of a piston 20 areadapted to seat upon the seats 15 and 16 and interrupt communicationbetween lines 2 and 3 and the chamber 6. It will be observed that thepiston 2() is reeiproeable in a cylinder 21, that it is normally held inthe position shown in be at once'readily apparent. When the coinpressoris running loaded the pressure in the intercooler will be substantiallyabove atinospheric, probably approximately one-halt the desired pressureto which the high pressure cylinder compresses the fluid pumped.Accordingly, at this time the Apiston 20 will be held up both by theintercooler pressure and by the pressure of the. spring 22; and the maX-imum pressure communicated from the high pressure Cylinder acting uponthe much smaller effective area of valve 17 exposed thereto will beinsuflicient to open the valves. When, however, the compressor isFunloaded and the intake closure valve operates to discontinue theadmission of fluid to the compressor intake, the intercooler pressurewill rapidly fall to less than atmospheric and accordingly the' piston20 will be moved downwardly; and the two ends of the cylinder will thenbe connected to each other through the lChamber 6; and when the pres irein the cylinder exceeds atmospheric pressilre it will force the valve 9off its seat and pass to the atmosphere through the passage 12. lVhenthe compressor isre- 'loaded and as soon as the intercooler pressurebuilds up to the necessary degree, the .valves 18 and 17 will seat andthe compressor will operate in a normal manner. It should be noted thata counter-bore 26 is provided at the lupper end ofthe bore '21 and ifthis is connected by a small port,26 to the atmosphere the opening ofthe valves will be more positive and continuous during unloaded running.

In the form of my invention shown in Figs. 4, 5, and 6, instead of usinga pair of end seating valves to control communication between the pipes2 and 3, and between them and the atmosphere, I have provided slidevalve mechanism for accomplishing this same function. Herein it will benoted that the parts 20, 21, 22, 23, and 24, 25 and 26, are to allintents and purposes identical with those previously described andreferred to by these saine numbers, but instead of employing the poppetvalves a pair of slide valves 31 and 32 are provided. These valves arereciproeable in ehamberst33 and 34 respectively communieating with thepipes 2 and 3 and opening through ports 35 and 36 into a recess 37corresponding to the recess 8. A suitable valve 39 and spring 40 areprovided for controlling the venting of fluid tothe atmosphere; and asuitable atmospheric vent 41 corresponding to the vent 12 may further beprovided. It will be noted that the ports 35 and 36 open through a flatvalve seat surface 42 and that the valves have flat faces 43.and 44cooperating with these seais. The valves are held in position byparallel lugs 45 seating in cutaway por- 70 tions 46 on a stem 47projecting upwardly from the piston 20, and springs 48 lodged inrecesses 49 within the stem maintain these valves seated. As the mode ofoperation vis precisely like that previously described except that uponunloading the valves move downwardly and uncover the passages 35 and'36by sliding off them, no further description of this form of my inventionseems necessary.

In Fig. 7 a still further and more pro- 80 nouncedly modifiedconstruction is presented. In this case the pipes 2 and 3 leading to thecounterbores at the opposite ends of thecylinderl open into annulargroovesn 52 and 53 formed in the inner .walls of a eyljndrically g5bored housing 54. Within the bore 55 of this housing a piston 56 isreciprocable, and this piston is normally maintained in the positionshown in Fig. 7 by a. spring 58 which cooperates withian Vadjustablefollower 59 at its 90 elower end. This'follower is adjusted by a screw6'0 in a manner similar to the adjustments of the previouslydescribedsprings. A

' connection 6 1 leads oil to the intcnplgr from the space within thebore 55 at the lo er side 95 of the piston 56. At its upper side thepiston i, 56 carries 'an upwardly extending -boss 62 which at itsextreme upper end-is provided with an enlarged portion providing a valveseating surface 63 upon which an annular 100 valve 64 is normally heldseated by a resilient bowed spring 65 held in position by'a screw 66. Acover 67 threaded as at 68 to the top of the casing member 54\enclosesthe valve mechanisin and provides a shoulder 69 against which the,outermost portion of .the valve seat is adapted to rest. An atmosphericvent is shown at 70 from the chamber 71 in which the valve is mounted.The space between-the enlarged portion carrying the valve seat 63 and110 the. portion 56 is sufficient to connectv the grooves 52 and 53 whenthe parts have moved to bottom position.

In the operation of this mechanism it will be evident that whenintercooler pressure falls below atmospheric pressure to the iequisitedegree, the piston 56 and all the connected parts will move downward,and that the piston, having `moved downward, will uncover the annulargrooves 52 and 53 and 12e they will. be freely in communication witheach other through the space surrounding the boss 62. As the pistonmoves downward its valve seat portion will also move downward in a likemanner and as a result there will 'occur a separation between the valveseat and the shoulder 69.r Any `pressure admitted to cient to overcomethe pressure of the spring 65 will unseat the valve 64 and be vented tothe atmosphere. On reloading, the parts will move up to the positionshown in Fin'. 7 again.

It will be evident that in all forms otmy invention which I haveillustrated herein there will be an automatic avoidance of any harmfultemperatures, and that the opposite ends of the cylinder willbe broughtinto communication with eachother before the pressure in the intake tothe high pressure cylinder is lowered to any substantial extent belowatmospheric pressure. It is furthermore evident that simultaneously withthe opening of communication between the ends of the cylinder, an outletto the atmosphere is provided for the fluid as fast as it reaches alittle above atmospheric pressure.

While I have in this application specifically described severalembodiments which my in- .vention may assume in practice, it will beunderstood that these forms of the same are shown for purposes ofillustration and that the invention may be modified and embodied invarious other forms without departing from its spirit or the scope ofthe appended clai-ms.

What I claim as new and desire tosecure by Letters Patent is:

1. In an unloading mechanism, in combination, a casing having chambersrespectively communicating with the opposite ends of a compressorcylinder, an intermediate chamber communicating with the atmosphere,valve means operative to connect said first mentioned' chambers withsaid intermediate chamber and through the latter with each other, andmeans directly responsive to intercooler pressure for controlling theposition of said valve means.

'2. In an unloadingmechanism, in'combination, a casing having chambersrespectively communicating with the opposite ends of a compressorcylinder, an intermediate chamber communicating with the atmosphere, endseating valve means operative to connect said first mentioned chamberswith said intermediate chamber and through the latter with each other,and means directly responsive to intercooler pressure for controllingthe position of said valve means.

3. In an unloading mechanism, a casing having chambers respectivelycommunicating with the opposite ends of a compressor cylinder, anintermediate chamber communicating with the atmosphere, end seatlng s1-multaneously movable valve means operative to connect said Iirstmentioned chambers with said intermediate chamber and through the latterwith each other, and intercooler pressure responsive means forcontrolling the position of said valve means. c

4. vIn an unloading mechanism, a casing havingl chambers respectivelycommunicating with the opposite ends of a compressor cylinder, anintermediate chamber communieating with the atmosphere, end seatingvalvemeans simultaneously movable in the same directions and operative toconnect said first mentioned chambers with said intermediate chamber andthrough the latter with each other, and intercooler pressure responsivemeans for controlling the position of said valve means. i

5. In an unloading mechanism, a casing having chambers respectivelycommunicating with the opposite ends of a compressorcylinder, anintermediate chamber communicable with the atmosphere, spring loadedvalve means controlling said communication, valve means loperative toconnect said lirst mentioned chambers with said intermediate chamber andthrough the latter with each other, and intercooler pressure responsivemeans for controlling the position of said valve means.

6. In an unloading mechanism, a casing having chambers respectivelycommunicating with the opposite ends of a compressor cylinder, anintermediate chamber communicable with the atmosphere,` spring loadedvalve means controlling said communication, end seating valve meansoperative to connect said first mentioned chambers with saidintermediate chamber and through the latter with each other, andintercooler pressure responsive means for controlling the position ofsaid valve means.

7. In an unloading mechanism, a casing having chambers respectivelycommunicating with the opposite ends of a compressor cylinder, anintermediate chamber communicable with the atmosphere, spring loadedvalve means controlling said communication, end seating simultaneouslymovable valve means operative to connect said lirst mentioned chamberswith said intermediate chamber and through the latter with each other,and intercooler pressure responsive means for controlling the positionof said valve means. l

8. In an unloading mechanism, acasing having chambers respectivelycommunicating with the opposite ends of a compressor cylinder, anintermediate chamber communicable with the atmosphere, spring loadedvalve means controlling said communication, end seating valve meanssimultaneously movable in the same directions and operative to connectsaid first mentioned chambers with said intermediate chamber and'through the latter with each other, and intercooler ,pressure responsivemeans for controlling the position of said valve means.

y 9. In an unloading mechanism, means forming a pair of chambersrespectively communicating with the opposite ends of a high pressurecylinder, each of said chambers being further provided with 'a portadapted to connect the same to the atmos- Cii phcie, valve meansrespectively controlling said atmospheric ports, and a single actuatingmeans directly controlled by lntercoolerY vJressure c Vlinder atmos)heric vent means l a a valve means respectively controllinglcomn'iunication of said chambers with saidatmospheric vent/means, andmeans including a single piston normally held in position to close saidvalve means and movable in accordance with pressure variations resultingfrom unloading for simultaneously moving` said valve means to openpositions.

12. In an unloading mechanism, a casing having chambers respectivelycommunicating with the opposite ends of a compressor cylinder,atmospheric vent means, valve means controlling the intercommunicationbetween said chambers and their communication with said atmosphericventmeansand common means controlled by pressure variations resulting fromunloading for controlling `the position of said valve means andoperative to effect such intercommunication between said chambers.

13. In an unloading mechanism for the high pressure cylinder of acompound compressor, a casing.. having chambers respectivelycommunicating with the opposite ends of a compressor cylinder,atmbspheric vent means, and means movable in accordance with variationsin pressure growing out of unloading the compressor forsimultaneouslyproviding access between said chambers and with said atmospheric ventmeans.

14. n unloading mechanism adapted for connection to a compressorcylinder comprising multi-valve means movable as a unit to effect anunloading controlling function simultaneously with respect to the twoends of acompressor cylinder, and vacuum controlled means for effectingthe movement of said valvemeans.

15. An unloading mechanism adapted for connection to a compressorcylinder comprising means forming uid conducting passages adapted tocommunicate respectively with the end s of a compressor cylinder, valvemeans individual to each passagevfor controlling flow of fluid from thecompressor to the atmosphere by way of said passages, common means .foralways maintaining said valve means m an open position while thecompressor is vunloaded to permit'uid in said compressor to bedischargedto the atmosphere, and one-way flow control means for preventing backflow of fluid to said compressoi'. l

16. An unloading mechanism adapted-for connection to a compressorcylinder comprising means forming fluid conducting 'passages adapted tocommunicate respectively with the ends of la compressor cylinder, valvemeans for interconnecting'said passages and for connecting the same toatmosphere whereby the ends'ofthe compressor cylinder may be placed incommunication with each other and the fluid in the compressor dischargedto the atmosphere, and one-way flow cont-rol means .connection to acompressor cylinder comprising a casing provided with fchambers adaptedfor'cennection respectively with the ends-of a compressor cylinder,means comprising a unitary valve mechanism for interconnecting saidchambers and connecting the same to atmosphere whereby an unloadingfunction with respect to both ends of the cylinderis effectedsimultaneously, and intercooler pressure-responsive means for con-`trollinr said unitary valve mechanism. 18. n unloading mechanism adaptedfor connection to a compressor cylinder operative to effect unloading byventing and to allow communication between the ends of a compressorcylinder including passage forming means adapted for connection to theopposite ends of a cylinder, and a unitary valve mechanism forcontrolling intercommunication between said passage forming means andeffecting unloading by venting.

19. An unloading mechanism adapted for.

connection to a compressor cylinder comprising valve means movable as aunit to interconnect the ends of a compressor cylinder, and meanscontrolled by cylinder intake pressure controlling said valve means.

In testimony whereof I aiix my signature.

HALBERT B. HALvoRsEN.

CERTIFICATE 0F CORRECTION.

Patent No. 1,708,171. Granted April 9, 1929. to

HALBERT B. HALVORSEN.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 4,line 101. claim i8, for the word "communication" readintercommunication", und line 105, for the word "interconununication"read "communication"; and that 'the said Letters Patent should he readwith these corrections therein that the same may conform to the recordof the case inV the Patent Office.

Signed and sealed this 7th day of May, A. D. 1929.

M. J. Moore, (Seal) Acting Commissioner of Patents.

